Indexing apparatus

ABSTRACT

An indexing apparatus for indexing an article about an axis. The indexing apparatus is adapted to be removably attached to the article and is constructed to axially displace the article along the axis to a disengaged position upon the initial application of a rotary force to an indexing assembly housed within the indexing apparatus. When in the disengaged position, the article can be selectively rotated about the axis by the further application of rotary force to the indexing assembly so that the article may be positioned in a predetermined angular position. The indexing apparatus further includes locking pins for locking the article in a plurality of predetermined angular positions when the application of rotational force to the indexing assembly is discontinued.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to indexing apparatuses and, more particularly, is directed to indexable apparatuses for selectively orienting objects such as workholding devices in precise predetermined positions.

2. Description of the Invention Background

A number of different apparatuses have been developed for indexing a variety of articles between manufacturing operations to increase the efficiency of the manufacturing process. For example, various types of indexing apparatuses are typically used to accurately present a workpiece in a predetermined orientation relative to the spindle of a machining device such as a milling machine or the like.

One type of such indexing device is disclosed in U.S. Pat. No. 2,339,986 to Engert. The device in that patent comprises an indexable device for indexing a shaft into a variety of different machining orientations about a single axis. While this device advantageously can support a shaft in various orientations to enable, for example, keyways to be cut in different locations on the shaft, the device can only hold a single shaft at a time and is ill-suited for supporting non-cylindrical workpieces.

Another indexable device is disclosed in U.S. Pat. No. 3,020,998 to Webb. That device comprises a turntable adapted to be indexed by the cyclic operation of a ratchet and pawl mechanism. A plurality of vise-like workholders are supported on the table and are adapted to be indexed about an axis such that the workholders can be positioned in various orientations relative to metal bending or crimping apparatus. This device, however, can only support workpieces in single planar orientations about the device's axis. Moreover, the ratchet and pawl system cannot be used to index the workholders to very precise and minute different angular orientations.

U.S. Pat. No. 2,369,425 to Becker discloses an indexable workholding device that comprises a frame that is adapted for attachment to the machining table of a machining device such as drill press. A disk is rotatably attached to the frame and may be rotated about an axis and secured in a predetermined position by clamping members attached to the frame. The top of the disk is also configured to accept workpiece holding clamps thereon. The outer edge of the disk is provided with a vernier scale that cooperates with an indicator on the frame to very precisely indicate the rotational position of the disk relative to the frame. The workpiece accuracy is dependent upon the upon the secure clamping of the disk in position and the secure clamping of the workpiece on the disk. If either the workpiece or the disk moves even slightly, the workpiece accuracy will be compromised. A similar apparatus for retaining workpieces at selective angles is also disclosed in U.S. Pat. No. 2,406,043 to Sorensen. That device also comprises a rotatable plate member that is equipped with a plurality of threaded apertures adapted to receive workholding clamping members therein. Although this device is capable of indexing a workpiece at relatively precise angular orientations, if the clamping assemblies attaching the workpiece move, the workpiece accuracy is compromised.

All of the above indexing apparatuses have limitations. In particular, those apparatuses that can position an item or workpiece in a relatively accurate position are generally incapable of supporting the workpiece in a very accurate and rigid position when it has external forces, such as those typically generated by various machine tools, assembly apparatuses or other manufacturing devices applied thereto. Such indexing apparatuses that do provide an adequate degree of rigidity typically cannot achieve the desired positioning accuracy or they are expensive to manufacture and maintain.

A number of indexing apparatuses typically can only index items about a vertical or horizontal axis or they can only index items that are received or oriented in a common plane. Such indexing apparatuses are not well suited for use in those applications wherein it is desirable to present multiple surfaces of multiple workpieces to the spindle of a machining device. It will be appreciated that by indexing a workpiece relative to the spindle of a machining device, several workpiece surfaces typically may be machined without the necessity of removing the workpiece from the workholder and re-clamping it in other machining orientations.

One device that addresses this problem is manufactured by Chick Machine Tool, Inc. of 800 Commonwealth Drive, Warrendale, Pa. 15086 under the trademark "Multi-Lok". This devise comprises a vise-like clamping assembly that is equipped with first and second movable jaw supports to which first and second jaw members may be removably attached. A fixed center jaw is attached between the movable jaws to provide two workpiece holding stations. Multiple two-station clamping assemblies can be received on a common column member that has a plurality of slide receiving slots therein. A column supporting base plate can be selectively attached to the end of the column to enable the column to be attached to an indexable workholding table and thus enable the column to be selectively rotated relative to the spindle of, for example, a horizontal CNC milling machine. Such device, however, relies on an indexing mechanism that is a part of the milling machine. As such, it cannot be used to index workpieces on other machining devices that are not equipped with such indexable support members.

Another multiple workholding device manufactured by Chick Machine Tool, Inc., under the trademark "Multi-Dex", is also well-suited for clamping and selectively indexing a plurality of workpieces within the machining envelope of a machining device. This workholding device, in general, comprises a column member that supports a plurality of vise-like clamping assemblies that are similar to the Multi-Lok assemblies described above. However, the column member has a base plate formed thereon or attached thereto that may be attached to a selectively indexable support apparatus. Examples of selectively indexable supports are disclosed in U.S. Pat. No. 4,991,463 and U.S. Pat. No. 4,884,474 both to Kawata. Such assembly can be automatically indexed without the aid of hydraulic or electrical power, simply by contacting an actuator member with the machining device's spindle or the tool that is attached thereto. When a single two-station workholding device is indexed, the two workpieces retained therein can be machined on three sides before they must be removed from the workholder. Because the workholders described immediately above provide means for indexing four two-station workholders, a total of twenty four machining sequences (two workpieces/workholder×three sides/workpiece yields six exposed sides for machining sequences×four workholders) can be performed before the workpieces have to be removed from the workholders to be reoriented if necessary. Such device therefore increases the machine operator's "walk away" time (i.e., the time the machine can advance through preprogrammed machining sequences without the aid of an operator to relocate or reposition the workpiece(s)) and, thus, increases the machining apparatus efficiency. However, this device is adapted to be actuated by the machining apparatus itself and, thus, is not well adapted for manual actuation. Moreover, due to the types of gears used to lock the workholder in various angular positions, very precise accuracies of, for example, three arc seconds, cannot be achieved.

Thus, there is a need for an apparatus capable of indexing one or more items to very precise orientations about an axis that can also rigidly retain such items in that orientation when the items are under the influence of external forces.

There is a further need for an indexing apparatus that has the above-mentioned attributes that is relatively inexpensive to manufacture and maintain.

There is yet another need for an indexing apparatus that can be can be easily adapted to index items about a horizontal or a vertical axis.

There is a need for an indexable workholding apparatus that can selectively support a plurality of workpieces or workholders in very accurate angular orientations.

There is a further need for an indexable apparatus that can be easily used in connection with a variety of different machining apparatuses.

SUMMARY OF THE INVENTION

In accordance with a particular preferred form of the present invention, there is provided an apparatus for selectively indexing an article about an axis. The apparatus, in a preferred form, comprises a housing member and a first toothed ring that is non-rotatably attached to the housing member. The apparatus also includes a second toothed ring that is attached to the article and is axially and rotatably supported by the housing member. The second toothed ring is arranged in confronting relationship with the first toothed ring for selective meshing engagement therewith. The apparatus further includes a piston member rotatably supported within the housing member and is adapted to receive a rotary force. The piston member also defines at least one first ramped surface. Additionally, a preferred apparatus comprises a displacement assembly that is attached to the second toothed ring and has a corresponding displacement member cooperating with each of the first ramped surfaces such that when a rotary force is initially applied to the piston member, each first ramped surface causes the corresponding displacement member to axially bias the second toothed ring out of meshing engagement with the first toothed ring to a disengaged position and thereafter permits the second toothed ring and article to be selectively rotated about the axis upon the further application of rotary force to the piston member. The apparatus also includes a biasing member that is supported by the housing member for selectively biasing the second toothed ring into intermeshing engagement with the first toothed ring when further application of rotary force is discontinued.

In another preferred embodiment, the apparatus comprises a housing member and a first toothed ring non-rotatably attached to the housing member. A second toothed ring is axially and rotatably supported by the housing member and is arranged in confronting relationship with the first toothed ring for selective meshing engagement therewith. The second toothed ring is attachable to the article such that the article is indexed with the second toothed ring. A piston member is rotatably supported within the housing member and is adapted to receive a rotary force for rotating it about a first axis. The piston member has at least one roller member operably attached thereto that is arranged to rotate about a second axis that is substantially perpendicular to the first axis. This embodiment also comprises a displacement assembly that is attached to the second toothed ring and has a ramped surface that corresponds to each roller member. Each ramped surface cooperates with each corresponding roller member such that when a rotary force is initially applied to the piston member, each roller member causes a corresponding ramped surface on the displacement assembly to axially bias the second toothed ring out of meshing engagement with the first toothed ring to a disengaged position and thereafter permits the second toothed ring and article to be selectively rotated about the first axis upon the further application of rotary force to the piston member. This embodiment of the present invention also comprises biasing means that is supported by the housing member for selectively biasing the second toothed ring into intermeshing engagement with the first toothed ring when further application of rotary force is discontinued.

In yet another embodiment of the present invention, an indexable workholding apparatus is disclosed. In a preferred form, the indexable workholding apparatus comprises a longitudinal column member that has a first longitudinal axis and operably supports at least two pairs of selectively movable jaw members for selectively clamping workpieces therebetween. Each pair of jaw members is selectively movable along slots in corresponding second longitudinal axes that are substantially parallel to the first longitudinal axis. First and second support members are provided for rotatably and axially supporting the longitudinal column therebetween for selective axial and rotational movement relative to the first longitudinal axis. The apparatus further comprises an indexing assembly that is attached to the second support member and communicates with the longitudinal column member. The indexing assembly comprises one of the indexing apparatus embodiments described above and is adapted to selectively axially displace the column member along the first longitudinal axis to a disengaged position when a rotary force is applied to the indexing assembly, to permit the column member to thereafter be selectively rotated to a predetermined angular position about the first longitudinal axis upon the further application of rotary force thereto, and to selectively retain the column member in the predetermined angular position when the application of rotary force is discontinued.

Thus, it is an object of the present invention to provide an indexable apparatus that can be used to index a variety of different articles about an axis to very precise angular orientations.

It is another object of the present invention to provide an indexable apparatus with the above-mentioned attributes that can rigidly retain the article(s) attached thereto in the predetermined angular orientation(s).

It is yet another object of the present invention to provide an indexable workholding apparatus that can selectively support a plurality of workpieces within the machining envelope of a machining device at very precise angular orientations.

It is a further object of the invention to provide an indexable workholding apparatus that can be easily manually indexed to very precise angular orientations.

It is yet another object to provide a device which is lightweight to avoid overloading the machine tool's drives.

It is another object to provide a device which is compact to facilitate the support of a greater number of workholding systems and workpieces on the machine tool.

Accordingly, the present invention addresses the foregoing problems associated with other indexable apparatuses. The present invention also enables a plurality of workpieces to be selectively indexed to and firmly retained in very precise angular orientations relative to the spindle of a machining apparatus. Thus, the present invention serves to further maximize the use of the machining envelope and thereby minimizes the amount of machine downtime encountered when using other devices. The subject invention can be easily actuated by the manual application of force thereto and thus does not require the machine tool device to provide the actuation force. In addition to those advantages, other details, objects, and advantages will become apparent as the following detailed description of the present preferred embodiments hereof proceeds.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings, there are shown present preferred embodiments of the invention wherein like reference numerals are employed to designate like parts and wherein:

FIG. 1 is a cross-sectional view of a preferred indexable device of the subject invention with the indexing assembly thereof in an engaged position, with some of the elements thereof shown in full view for clarity;

FIG. 2 is another cross-sectional view of the indexable device of FIG. 1 with the indexing assembly thereof in a disengaged position, with some of the elements thereof shown in full view for clarity;

FIG. 3 is a side view of a preferred piston member of the indexable device of FIGS. 1 and 2 with a portion thereof shown in cross-section;

FIG. 4 is a top view of the piston member of FIG. 3;

FIG. 5 is a partial cross-sectional view of a portion of the piston of FIGS. 3 and 4 showing a preferred bearing race configuration;

FIG. 6 is a preferred ramping profile of the bearing race of FIG. 5;

FIG. 7 is an isometric view of a preferred indexable device of the present invention supporting a preferred workholding assembly on an apertured grid plate;

FIG. 8 is side elevational view of the indexable workholding assembly of FIG. 7;

FIG. 9 is an end elevational view of the front end of the indexable workholding assembly of FIGS. 7 and 8;

FIG. 10 is an end elevational view of the opposite end of the indexable workholding assembly of FIGS. 7-9;

FIG. 11 is a partial cross-sectional side elevational view of a column member of an indexable workholding assembly, with some of the elements thereof shown in full view for clarity;

FIG. 12 is an end elevational view of the column of FIG. 11 with some of the elements thereof shown in cross-section;

FIG. 13 is a partial cross-sectional assembly view of a column received on a preferred front support member of an indexable workholding apparatus of the present invention showing some of the elements thereof in full view for clarity;

FIG. 14 is a partial cross-sectional assembly view of a column received on a preferred rear support member, with some of the elements thereof shown in full view for clarity;

FIG. 15 is a cross-sectional view of another preferred indexable device of the subject invention with the indexing assembly thereof in an engaged position, with some of the elements thereof shown in full view for clarity;

FIG. 16 is another cross-sectional view of the indexable device of FIG. 15 with the indexing assembly thereof in a disengaged position, with some of the elements thereof shown in full view for clarity; and

FIG. 17 is a partial cross-sectional assembly view of the indexable device mounted to a preferred rear support member for supporting a column, with some of the elements thereof shown in full view for clarity.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now to the drawings for the purposes of illustrating present preferred embodiments of the invention only and not for purposes of limiting the same, FIGS. 1 and 2 illustrate a preferred indexable apparatus 10 that has a housing 11 that can be operably attached to variety of different support structures (not shown) to orient the device's axis of rotation "A--A" in a desired orientation. As the present Detailed Description of Preferred Embodiments proceeds; the reader will appreciate that the present indexable device 10 may be used in a variety of different applications wherein it is desirable to index an item or a plurality of items about an axis at preferred increments of, for example, 5° at a very high accuracy of, for example, approximately ± three arc-seconds.

More particularly and with reference to FIGS. 1 and 2, the present indexing apparatus 10, in a preferred form, includes an indexing coupling 20 commonly known in the art as a "Curvic-type" or "Hirth-type" coupling. The indexing coupling 20 comprises a first indexing or toothed ring 22 and a second indexing or toothed ring 70 adapted for meshing engagement with the first toothed ring 22. As can be seen in FIGS. 1 and 2, an object 15 that is to be indexed is non-rotatably attached to the second toothed ring 70 preferably by cap screws 17 that are received in threaded bores 71 in the second toothed ring 70. The skilled artisan will appreciate that object 15 can comprise a variety of different items such as, for example, workholders for holding one or more workpieces therein, such as that disclosed in U.S. Pat. No. 4,529,183. It will be further appreciated that the object 15 may be attached to the second toothed ring 70 by other suitable methods without departing from the spirit and scope of the present invention.

The first toothed ring 22 is attached to the housing 11, preferably by cap screws 24 and has two bores (26, 27) therein that are coaxially aligned on axis "A--A". Coaxially received within the bores (26, 27) is a displacement assembly, generally designated as 28. The displacement assembly 28 cooperates with, among other things, a rotary piston assembly 30 and a locking cylinder 60. In a preferred embodiment, the piston assembly 30 comprises a piston member 32 that is rotatably housed within the locking cylinder 60 and a bearing ring 40 that is attached to the second toothed ring 70. As can be seen in FIGS. 1-3, the piston member 32 includes a first actuator portion 33 that preferably has a hexagonally-shaped bore 34 therein. As will be discussed in further detail below, bore 34 is preferably adapted to receive an actuator such as, for example, an allen wrench for actuation purposes. However, other actuating devices could also be successfully used.

Piston member 32 is also preferably formed with first and second grooves (35, 36) that each support an O-ring 37 around its outer perimeter for establishing a substantially fluid-tight seal between the grooves (35, 36) and the locking cylinder 60. Grooves (35, 36) are spaced-apart to define a grease receiving cavity 38 therebetween. In addition, a stub axle 39 is attached to an end of piston member 32 preferably by a capscrew (not shown). As can be seen in FIGS. 1 and 2, stub axle 39 is sized to be rotatably received in a sleeve bearing 13 supported in a coaxial bore 12 in housing 11.

Cooperating with piston member 32 is bearing ring 40 that has a hub portion 41 that is received within a coaxial bore 72 in the second toothed ring 70. An O-ring 42 is preferably mounted in hub portion 41 to prevent the intrusion of debris into the apparatus 10. Bearing ring 40 also has a flanged portion 43 that is attached to the locking cylinder 60 and the second toothed ring 70, preferably by capscrews 44. Hub portion 41 has a bore 45 therethrough that is adapted to receive the actuator portion 33 of the piston member 32 therein. In addition, a sleeve bearing 46 is mounted in hub portion 41 to provide radial support to the actuator portion 33 of the piston 32. A conventional shaft seal 47 is provided to prevent the intrusion of debris into the apparatus 10.

In a preferred embodiment, the piston assembly 30 and the retaining member 40 cooperate to support at least one, and preferably, a plurality of (preferably two) balls 48 therebetween. More particularly and with reference to FIGS. 1-3, the first flange 35 of the retaining member 40 has two semi-circular bearing races 49 machined therein. Each race 49 preferably extends around the actuator portion 33 approximately 130° (represented by angle "D" in FIG. 4). Preferably, the races 49 are ramped (i.e., races 49 are each shallower at their ends 50 than their ends 52). FIG. 6 depicts a preferred ramping profile of a race 49. As can be seen in that Figure, each race 49 is preferably ramped as follows: at 0°, the race 49 is essentially horizontal; at 5°, the race 49 begins to ramp; and at 130°, the race 49 is preferably approximately 0.080" above horizontal (represented by distance "E" in FIG. 6).

Also in a preferred embodiment, corresponding races 55 are provided in the surface 54 of the bearing ring which is in confronting relationship with the first flange 35 in the piston member 32. See FIGS. 1 and 2. Races 55 are preferably mirror images of races 49 and cooperate with races 49 to form ball cavities, generally designated as 56. Balls 48 are preferably retained within ball cavities 56 by a ball cage member 57.

As can also be seen in FIGS. 1 and 2, the first and second toothed rings (22, 70) are preferably biased into meshing engagement by a plurality of Belleville washers 76 that are received on the locking cylinder 60 as shown in FIGS. 1 and 2. Preferably, three Belleville washers 76, sized to create a meshing force of approximately 1500 pounds, are coaxially received with a thrust washer 78 in bore 27 in the first toothed ring 22. As can also be seen in FIGS. 1 and 2, a conventional bearing member 80 is received on the locking cylinder 60 to provide rotational support to the thrust washer 78 and, ultimately, to the displacement assembly 28.

As can be seen in FIGS. 1 and 2, one end of the locking cylinder 60 has a flanged portion 62 which preferably supports at least one spring-biased detent pin 90. More particularly, one or more radial bores 66 are provided in the flanged portion 62 of the locking cylinder 60 and are sized to slidably receive therein a corresponding detent pin 90. Preferably, each detent pin 90 has an oversized transverse bore 92 therethrough that is adapted to receive a transverse pin member 68 attached to the flanged portion 62 as shown in FIGS. 1 and 2. The reader will appreciate that the transverse pin 68 serves to movably retain the detent pin 90 within the radial bore 66. A coil spring 94 is provided between the detent pin 90 and the bottom of the bore 66 to bias the detent pin 90 in an outward radial direction. In a preferred embodiment, a cavity 14 in the housing member 11 is provided with engagement notches 16 that are preferably arranged at 90° intervals for engagement by detent pins 90. Those of ordinary skill in the art will appreciate, however, that any number of engagement notches 16 may be provided in the inner wall of the cavity 14. Each engagement notch 16 is adapted to receive one or more detent pins 90 such that when the end of the detent pin 90 is received within one of the notches 16, the indexing assembly 28 is further retained in that angular position. As can also be seen in FIGS. 1 and 2, a commercially available wiper member 64 is provided between the second toothed ring and the locking cylinder 60 to prevent debris from entering bore 27 when the second toothed ring is biased to the disengaged position illustrated in FIG. 2.

Also in a preferred embodiment, to provide an indication of the angular position of object 15 about axis "A--A", an angular scale member 74 is attached to the perimeter of the second toothed ring 70 such that it travels therewith. The scale member 74 is also provided with an annular portion 75 that is adapted to be selectively received within a bore 77 in the housing 11. Scale member 74 cooperates with "witness marks" on the housing 11 (not shown) to provide the operator with a visual indication of the angular position of the second toothed ring 70 and, ultimately, the object 15.

Preferably received within annular grooves 81 in the housing 11 are commercially available wiper members 83. Additional wiper members 87 are preferably received in annular grooves 85 in the scale member. As will be discussed in further detail below, wipers 83 serve a two-fold purpose; namely, to prevent chips and debris from entering into the bore 77 and to provide a sufficient amount of frictional force to retain the second toothed ring 70 in a momentary "disengaged" position as the piston assembly 30 is being rotated through the final portion of its angular path.

The operation of the indexable device 10 is, essentially, a two step process and can be understood from further reference to FIGS. 1 and 2. FIG. 1 illustrates the displacement assembly 28 in an "engaged" position wherein the first and second toothed rings (22, 70) are biased into meshing engagement by the force created by the Belleville springs 76. Thus, to index the object 15, the second toothed ring 70 must first be axially advanced out of meshing engagement with the first toothed ring 22. To accomplish that task, a rotational actuation force is initially applied to the first actuator portion 33 to cause it to rotate in a clockwise direction about axis "A--A". Such rotational force may be applied by inserting an allen wrench into bore 34 in the actuator portion 33 of piston 32 and manually applying torque thereto.

The piston member 32 is rotated through a preferred 260° path of rotation that is limited by the races (49, 55). As the piston member 32 is rotated and the bearings are advanced up the ramped races (49, 55), the bearing ring 40 and the second toothed ring 70 are axially advanced in the "C" direction to disengage the second toothed ring 70 from the first toothed ring 22. It will be appreciated that the displacement assembly 28 is constructed to provide the requisite mechanical advantage to sufficiently compress the Belleville springs 76 to permit the second toothed ring 70 to be biased out of meshing engagement with the first toothed ring 22. As was mentioned above, in a preferred embodiment, the Belleville springs 76 are preferably sized to provide approximately 1500 pounds of meshing force to the first and second toothed rings (22, 70). However, the Belleville springs 76 and the displacement assembly 28 may be appropriately sized to provide any other suitable meshing force.

In a preferred embodiment, the wipers (83, 87) are sized and so positioned to create frictional rotational forces between the scale member, the housing 11 and the first toothed ring 22. The skilled artisan will appreciate that wipers (83, 87) serve to create frictional forces that are somewhat greater than the rotational force required to operate the displacement assembly 28. Those frictional forces serve to overcome the forces required to operate the displacement assembly 28 including the forces created by the Belleville springs 76 which would otherwise cause the second toothed ring member 70 to axially move in the "B" direction and possibly contact the first toothed ring 22 while the piston member 32 is further rotated. When the balls 48 reach the ends 52 of races (49, 55), further rotation thereof causes the second toothed ring 70 and, ultimately, the object 15 to be rotated about the axis "A--A". It will be understood that while the frictional rotational force generated by the wipers (83, 87) is sufficient to overcome the rotational force required to operate the displacement assembly 28, such frictional force may be easily overcome by the further manual application of rotary force to the piston member 32. The skilled artisan will also recognize, however, that other mechanisms may be used to provide the requisite frictional force without departing from the spirit and scope of the present invention. After the object 15 has been rotated to a desired position, the shaft 19 is permitted to turn in a counterclockwise direction under the biasing force of the Belleville springs 76 which causes the second toothed ring 70 to re-engage the first toothed ring 22 and thus, rigidly retain the object 15 in that desired position. The rotation of the shaft 19 is retarded by the provision of damping grease in grease-receiving cavity 38.

As can be seen in FIGS. 7-14, the indexing device 10 of the present invention can also be most advantageously used in connection with a workholding column member 150 to create a selectively indexable workholding assembly 200 that can be attached to a grid plate 130 in a precise position for supporting a plurality of workpieces in various machining orientations relative to a machining device (not shown). It will be further appreciated that such grid plate 130 is adapted to be fastened to the machine table (not shown) of a machining apparatus such as a milling machine (not shown) by known fastening and locating means.

More particularly and with reference to FIG. 7, the workholding assembly preferably comprises a column member 150 that is rotatably supported by an indexable support apparatus, collectively designated as 210, that comprises, among other things, a "first" upstanding support member 220 and a "second" upstanding support member 300 that houses an indexable device 10 of the present invention therein. The column 150 depicted in the present Figures comprises an elongated metallic structure typically fabricated from a high strength aluminum material having four longitudinal surfaces 152 thereon. The skilled artisan will readily appreciate, however, the indexable support assembly 210 of the present invention can be used to support columns of various other shapes and constructions without departing from the spirit and scope of the present invention.

As can be seen in FIGS. 7, 13, and 14, the column 150 has a longitudinal axis "D'--D'" about which it can be selectively rotated. A longitudinally extending cavity 154 having a longitudinal axis "E'--E'" is preferably provided in each surface 152 of the column 150 such that each axis "E'--E'" is substantially parallel to axis "D'--D'". See FIG. 8. Each longitudinal cavity 154 defines a corresponding slot 156 having two longitudinally extending side rail members 157. See FIG. 12. In addition, a corresponding clamping assembly, generally designated as 160, is provided for longitudinal movement within each cavity 154. The clamping assemblies 160 are preferably of the type disclosed in U.S. Pat. No. 5,024,427, the disclosure of which is herein incorporated by reference. In addition, in this embodiment, the clamping assemblies 160 are preferably identical in construction. As such, a single clamping assembly will be herein described with it being understood that all of clamping assemblies 160 are of identical construction.

In general, a clamping assembly 160 preferably comprises a first movable support member 162 and a second movable support member 168 which are each adapted to be received within a corresponding slot 156 in the column 150. See FIG. 11. The clamping assembly 160 also preferably includes a screw shaft 174 that is sized to be received within a corresponding slot 156 in the column member 150. The screw shaft 174 preferably has threads 176 which are intended to engage a threaded bore 163 within the first movable support member 162. In addition, the screw shaft 174 includes means (not shown) for engaging and displacing the second movable support member 168 thereon. The screw shaft 174 passes through the second movable support member 168 while the other end of the screw shaft 174 is configured to receive an allen wrench or other apparatus for selectively supplying rotary motion to the screw shafts 174 received within the cavities 154 of the column 150.

A "first" center jaw 158 is preferably attached to each surface 152 intermediate the column ends in a predetermined position. In a preferred embodiment, each center jaw 158 is removably attached to its corresponding surface 152 by cap screws 159 that extend through corresponding bores 161 in the center jaw member 158. Preferably, locating bushings 175 are pressed into corresponding bores in each surface 52 and are coaxially arranged with threaded bores (not shown) in the column 150. One locating bushing 175 preferably has a round aperture therethrough and the other locating bushing 175 preferably has an elongated "slot" therethrough. The bushings 175 are adapted to receive therein the shoulder portions of corresponding capscrews 159 to precisely locate the center jaw 158 on the surface 152. Other locating pin arrangements that are known in the art may also be used to precisely locate each center jaw member 158 on a corresponding surface 152 of the column 150. For example, the locating arrangement such as the one disclosed in a copending U.S. patent application entitled "Apparatus For Positioning An Element On A Surface", Ser. No. 08/690,031, filed Jul. 31, 1996, owned by the owner of the present application, the disclosure of which is herein incorporated by reference, may also be used in those instances wherein it is desirable to have each center jaw 158 precisely located on and attached to each surface 152 of column 150.

As shown in FIG. 11, a "first" jaw member 180 corresponds with each first movable support member 162 and is preferably removably attached thereto. Similarly, a second jaw member 186 corresponds with each second movable support member 168 and is removably attached thereto. The jaw members (180, 186) are preferably similar to those workholding jaw portions disclosed in U.S. Pat. No. 5,024,427 entitled "Quick Change Head For Precision Machine Vise" the disclosure of which is also herein incorporated by reference. As such, in the present "Detailed Description Of Preferred Embodiments", the basic jaw structure of each clamping assembly 160 will be described in general terms, it being understood that the particular details of the jaw member construction, with the exception of those features which are described hereinbelow forming these embodiments of the present invention, may be gleaned from a review of that patent.

In general, as can also be seen in FIG. 11, each first movable support member 162 has a "first" extended portion 164 that extends above the corresponding surface 152. The first extended portion 164 has a "first" transverse bore 165 extending therethrough that has a "first" flat surface 166 machined therein. Similarly, each second movable support member 168 has a "second" extended portion 170 that extends above the corresponding surface 152. The second extended portion 170 has a "second" transverse bore 172 that extends therethrough that has a "second" flat surface 173 machined thereon. In addition, each first jaw member 180 preferably has a "first" cavity 182 therein that is sized to receive a "first" extended portion 164 of a corresponding first movable support member 162. A "primary" transverse bore 188 is preferably provided through the first jaw member 180 such that the primary transverse bore 184 will be substantially coaxially aligned with the first transverse bore 165 when the first extended portion 164 is received within the first cavity 182 in the first jaw 180. See FIG. 11. Also, each second jaw member 186 preferably has a "second" cavity 187 therein that is sized to receive a second extended portion 170 of a corresponding second movable support member 168. Also, a "secondary" transverse bore 188 is preferably provided through the second jaw member 186 such that the secondary transverse bore 188 will be substantially coaxially aligned with the second transverse bore 172 when the second extended portion 170 is received within the second cavity 187 in the second jaw member 186.

The first jaw members 180 are preferably removably attached to their corresponding first movable support members 162 and the second jaw members 186 are preferably removably attached to their corresponding second movable support members by removable pins 190. The preferred construction of pins 190 is set forth in detail in U.S. Pat. No. 5,024,427, the disclosure of which was incorporated by reference hereinabove. In general terms, however, each pin 190 has a planar portion 192 which is adapted to be brought into contact with the flat surfaces (166, 173) in bores (165, 172). In particular, each first jaw 180 is preferably removably attached to a corresponding first movable support member 162 by inserting a corresponding pin 190 through the coaxially aligned bores 184 and 165 such that the planar portion 192 of the pin 190 engages the first flat surface 166 of the first transverse bore 165. Similarly, each second jaw 186 is preferably removably attached to a corresponding second movable support member 168 by inserting a corresponding pin 190 through the coaxially aligned bores 188 and 172 such that the planar portion 192 of the pin 190 engages the second flat surface 173 of the second transverse bore 172.

As can be seen in FIG. 11, each center jaw 158 is arranged on a corresponding surface 152 of the column 150 such that the corresponding first and second movable support members (162, 168) may move toward and away from the corresponding center jaw member 158 to cause, for example, workpieces 153 and 155 to be clamped between the center jaw 158 and first and second jaws (180, 186). For example, when a screw shaft 174 is rotated, the first movable support member 162 is moved relative to the center jaw 158, thereby causing the first jaw 180 to move toward the center jaw 158 to clamp a first workpiece 153 therebetween. In addition, the rotation of the screw shaft 174 and its movement relative to the first movable support member 162 causes the second movable support member 168 to move toward the center jaw member 158 to cause the second jaw member 186 to engage and restrain a second workpiece 155 between the second jaw member 186 and the center jaw member 158.

Also, a debris shield 350, is preferably positioned between the surface and the corresponding first and second jaw members (180, 186) to prevent chips and debris from entering the longitudinal cavities 154. Preferably, the debris shield 350 has a first opening 352 therein adapted to receive a corresponding first extended portion 164 and a second opening 354 therein adapted to receive a corresponding second extended member 168. In addition, debris shield 350 has bores 356 adapted to receive bushings 175 therein. Debris shield 350 is preferably fabricated out of tool steel having a Rockwell hardness of approximately 50 (C scale). It will be appreciated that when the debris shield 350 is received on a corresponding surface 152 as shown in FIG. 11, the clamping assembly 160 is longitudinally retained within its corresponding cavity 154 by virtue of the debris shield's engagement with the bushings 175 in cooperation with the openings (352, 354) in the debris shield 350. It will be appreciated that openings (352, 354) are sized relative to the first and second jaw members (180, 186) such that regardless of where the first and second jaw members (180, 186) are located, the openings (352, 354) are always covered to prevent any debris from entering the longitudinal cavity 154.

As mentioned above, the column member 150 is rotatably supported on an indexable support assembly 210 that comprises a first upstanding support member 220 and a second upstanding support member 300 that are attachable to a grid plate 130. The first support member 220 is preferably fabricated from aluminum in the shape shown in FIGS. 3 and 9. However, the reader will appreciate that the first support member 220 can be fabricated from other suitable materials in various other shapes. Preferably, the first support member 220 has a lower support plate 222 attached thereto that is designed to support the first support member 220 on a grid plate 130 that has a plurality of bores 132 therein arranged in a predetermined array of orthogonally arranged rows and columns. "Tooling" or "grid" plates of this type are known in the art and, therefore, will not be discussed in great detail herein. However, in this embodiment, each bore 132 in the grid plate 130 preferably has a lower threaded portion 134 and a locating bushing 136 pressed therein that is fabricated from hardened tool steel. See FIG. 11. As can be seen in FIG. 9, the opposing lower ends (226, 228) of the first support member 220 are each preferably provided with a fastener cavity 230. Each fastener cavity 230 has a fastener bore 232 therein that is coaxially aligned with a corresponding very accurately sized bore 232 in the support plate 222. See FIG. 13. Preferably, a locating screw 234 having a very accurately ground locating shoulder is inserted through the fastener bores (232, 233) to be threadedly received in corresponding threaded bores 134 in the grid plate 130. It will be appreciated that the shoulder portion of the screw 234, in cooperation with the bushing 136, serves to accurately locate the first support member 220 on the grid plate 130. Such locating and fastening method advantageously permits the workholding assembly 200 to be slidably positioned on the grid plate 130 during the initial orientation thereof. Furthermore, those of ordinary skill in the art will appreciate that by locating the locating screws 234 inside of the first support member 220, the fasteners and the support member are less susceptible to damage than other prior designs. This method of locating and attaching the first support member 220 to the grid plate 130 is also preferably used to attach the second support member 300 to the grid plate 130. The skilled artisan will further appreciate, however, that the first and second support members (220, 300) can be attached to a grid plate or other member in precise relationship to one another by a myriad of other known locating and fastening methods and apparatus without departing from the spirit and scope of the present invention.

To prevent chips and debris from entering fastener cavities 230, while providing a means for accessing the capscrews 234, slidable chip covers (231, 233) are slidably and overlappingly received in corresponding receiving slots (223, 225). To gain access to the capscrews 234, the chip covers (231, 233) are simply slidably displaced within the grooves (223, 225).

As can be seen in FIG. 13, a shaft 240 is rotatably received within an axial bore 242 in the "front" end 151 of column 150 and is rotatably attached thereto by a stub shaft 244. Stub shaft 244 is preferably fabricated from bronze and is adapted to be non-rotatably received within a cavity 241 in the front end 151 of column 150. Preferably, stub shaft 244 is rigidly attached to column 150 by a plurality of (preferably four) capscrews 245 and has an axial shaft receiving bore 246 in which shaft 240 is rotatably supported. To prevent debris from infiltrating between the shaft 240 and the stub shaft 244, shaft 240 is preferably provided with an annular groove 250 adapted to receive therein a commercially available resilient wiper member 252.

Stub shaft 244 is also adapted to be rotatably received within a corresponding bore 254 provided in the upper portion of first support member 220. As can be seen in FIG. 13, the end of shaft 240 is preferably provided with a hexagonally shaped cavity 258 to receive a standard allen wrench or other tool to provide rotation to shaft 240 and ultimately to the actuator portion 33 of the piston member 32 to thereby cause column 150 to rotate about longitudinal axis "D'--D'". To prevent chips and debris from entering bore 254, an annular groove 255 is provided in the first support member 220 to retain a resilient endcap member 264 as shown in FIG. 13. End cap member 264 is preferably fabricated from rubber or similar material and has an access slit 266 therein through which an allen wrench or other suitable tool may be inserted. See FIG. 13. Also, to prevent chips and debris from entering the cavities 154 in the column 150, a plurality of end plate segments 142 are attached to the front end 151 of column 150 by capscrews 144 in the manner depicted in FIG. 12. Each end plate segment 142, preferably has an axial bore therethrough (not shown) that provides operational access to the end of the corresponding screw shaft 174. An endcap member 264 is also preferably attached to each end plate segment 142 to prevent chips and debris from accumulating in those axial bores. In a preferred embodiment, all but one of the endcap members 264 that are attached to the endplates 142 are similarly colored. It will be appreciated that the "odd" colored endcap 164 indicates a "starting" or reference position to enable the operator to track the rotational position of the column member 150. Also, to further prevent chip and debris infiltration between the stub shaft 244 and the bore 254 in the first support member 220, a resilient gasket member 268, preferably fabricated from foam rubber or similar material, is provided around stub shaft 244 as shown in FIG. 13.

The other end of the shaft 240 protrudes from the opposite end 151' of the column 150 and preferably has a hexagonal wrench portion 270 formed thereon. A cavity 272 is provided in column end 151' such that it is substantially coaxially aligned with the shaft 240 along axis "D--D". An alignment ring 274 is coaxially aligned within cavity 272 as shown in FIG. 14. Preferably, alignment ring 274 is retained within the cavity 272 by corresponding capscrews 276 and is adapted to assist in the alignment and engagement of wrench portion 270 with the bore 34' in the actuator portion 33' of the piston 32' as will be discussed below.

The second upstanding support member 300 is preferably fabricated from aluminum and is essentially the same as the housing 11 discussed hereinabove and houses a preferred indexable device 10' of the present invention that is identical in construction and operation to the indexable device 10 discussed in detail above, except for the following noted preferred differences. It will be appreciated that the second upstanding support member is also preferably located on and attached to the grid plate 130 in the manner discussed above. The column member 150 is attached to the second toothed ring 70' by a plurality of (preferably four) elongated screw members 322 that pass through bores 320 in the column 150 to be threadedly received in corresponding threaded bores 71' in the second toothed ring 70'.

To index the column 150 about the longitudinal axis "D'--D'", a wrench or other suitable tool is inserted into hexagonal cavity 258 in the one end of shaft 240 and the shaft 240 is thereafter rotated clockwise to cause the second toothed gear to be axially displaced along axis "D'--D'" under the initial application of rotary force to the piston assembly 30'. Thereafter, the further application of rotary force to the piston assembly 30' causes the column 150 to be rotated to a desired radial position. The reader will appreciate that the indexing apparatus operates in the manner discussed above to selectively index the column 150 to a desired orientation. The reader will further appreciate that the rotational force required to index the column 150 may be provided by a number of other sources such as electric motors, hydraulic motors, etc. After the column 150 is indexed to the desired position, the rotary force is discontinued, permitting the toothed rings (22', 70') to re-engage under the axial force created by the Belleville springs 76'.

Another embodiment of the present invention is depicted in FIGS. 15 and 16. In this embodiment, except for the differences described below, the construction of the apparatus 410 is identical to the construction of apparatus 10 as described above. Thus, the elements of apparatus 410 that are identical to the elements of apparatus 10 have been identified by like numbers. In this embodiment, the piston assembly 430 is fitted with a roller 452 that rotates about an axis H--H that is substantially perpendicular to axis A--A.

More particularly and with reference to FIGS. 15 and 16, the piston assembly 430 comprises a piston member 432 that is rotatably housed within the locking cylinder 60 and a retaining member 440 that is attached to the second toothed ring 70. The piston member 432 includes a first actuator portion 433 that preferably has a hexagonally-shaped bore 434 therein. As will be discussed in further detail below, bore 434 is preferably adapted to receive an actuator such as, for example, an allen wrench for actuation purposes. However, other actuating devices could also be successfully used.

Piston member 432 is also preferably formed with first and second flanges (435, 436) that each support an O-ring 437 around its outer perimeter for establishing a substantially fluid-tight seal between the flanges (435, 436) and the locking cylinder 60. Flanges (435, 436) are spaced-apart to define a grease receiving cavity 438 therebetween. In addition, a stub axle 439 is attached to an end of piston member 432 preferably by a capscrew (not shown). As can be seen in FIGS. 15 and 16, stub axle 439 is sized to be rotatably received in a sleeve bearing 13 supported in a coaxial bore 12 in housing 11.

Cooperating with piston member 432 is bearing ring 440 that has a hub portion 441 that is received within a coaxial bore 72 in the second toothed ring 70. Bearing ring 440 also has a flanged portion 443 that is attached to the locking cylinder 60 and the second toothed ring 70 preferably by capscrews 44. An O-ring 444 is preferably mounted in the flanged portion 443 to prevent the intrusion of debris into the apparatus 410. Hub portion 441 has a bore 445 therethrough that is adapted to receive the actuator portion 433 of the piston member 432 therein. An O-ring 446 is preferably mounted in bearing ring 440 to prevent debris from infiltrating between the actuator portion 433 and the bearing member 440.

In a preferred embodiment, a roller member 452 is mounted with the first flange 435. As can be seen in FIG. 15, the first flange 435 has a radial bore 449 therein that is coaxially aligned with axis H--H. A roller axle 450 is mounted within bore 449 and rotatably supports roller member 452 thereon. A cavity 451 is provided in the piston member 432 to facilitate the rotation of roller member 452 about the axle 450. In this embodiment, the roller member 452 is adapted to roll on a ramped surface 447 provided on the bearing ring 440. As the piston member 432 is rotated in a clockwise direction about axis A--A, the roller member 452 rolls up the ramped surface 447 thus causing the bearing ring 440 and, ultimately, the second toothed ring 70 to move axially in the "C" direction to a disengaged position. Further rotation of the piston member 432 then causes the second toothed ring 70 and object 15 to rotate about axis A--A to a desired position. After the object 15 has been indexed to a desired position, the piston member 432 is permitted to rotate in the counterclockwise direction under the force of the Belleville springs to cause the second toothed ring 70 to move in the "B" direction to reengage the first toothed ring 22. The skilled artisan will readily appreciate that this embodiment can also be used in connection with the above-described column arrangement as shown in FIG. 16.

The above-disclosed indexable workholding assemblies are just one of many applications in which the indexable devices of the present invention can be advantageously used. The present indexable devices can be used in numerous applications wherein an item or a collection of items must be very precisely indexed to positions about an axis and retained in those positions even under the influence of substantial external forces. The present indexable devices are relatively compact and can be incorporated into various other support structures as desired. In addition, when compared to a number of other indexable apparatuses, the present indexable devices are relatively inexpensive and easy to operate. Moreover, the present indexable apparatuses can generate very high retaining forces while maintaining the ability to be indexed by the manual application of rotary actuation force thereto. Also, the present invention provides solutions to the aforementioned problems associated with indexable vise-like workholding apparatuses. While such advantages are apparent from the foregoing disclosure, it will be understood, however, that various changes in the details, materials and arrangements of parts which have been herein described and illustrated in order to explain the nature of the invention may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims. 

What is claimed is:
 1. Apparatus for selectively indexing an article about an axis, comprising:a housing member; a first toothed ring non-rotatably attached to said housing member; a second toothed ring axially and rotatably supported by said housing member and arranged in confronting relationship with said first toothed ring for selective meshing engagement therewith, said second toothed ring being attached to said article; a piston member rotatably supported within said housing member and adapted to receive a rotary force, said piston member defining at least one first ramped surface; a displacement assembly attached to said second toothed ring and having a corresponding displacement member cooperating with each said first ramped surface of said piston member such that when a rotary force is initially applied to said piston member, each said first ramped surface causes said corresponding displacement member to axially displace said second toothed ring out of meshing engagement with said first toothed ring to a disengaged position and thereafter permitting said second toothed ring and article to be selectively rotated about said axis upon the further application of said rotary force to said piston member to rotate said article to a desired angular position about said axis; and biasing means supported by said housing member for selectively biasing said second toothed ring into said meshing engagement with said first toothed ring when said further application of said rotary force is discontinued.
 2. The apparatus of claim 1 wherein said piston member has a first bearing surface and wherein each said first ramped surface comprises a first ramped ball race in said first bearing surface and wherein said displacement assembly comprises a bearing ring attached to said second toothed ring and being coaxially aligned with said piston member and having a second bearing surface in confronting relationship with said first bearing surface of said piston member, said second bearing surface having a corresponding number of second ramped ball races therein that correspond to said first ramped ball races and cooperate therewith to define at least one ball cavity for receiving a corresponding ball member therein.
 3. The apparatus of claim 1 wherein said biasing means comprises at least one spring washer in said housing member for forcing said first and second toothed rings into engagement.
 4. The apparatus of claim 1 further comprising means for retaining said second toothed ring in said disengaged position after said initial application of rotary force and prior to the further application of said rotary force to said piston member.
 5. The apparatus of claim 4 wherein said means for retaining comprises:an axial annular cavity in said housing member; an annular ring member attached to the perimeter of said second toothed ring and arranged for axial travel within said axial annular cavity in response to said axial displacement of said second toothed ring; and at least one wiper member attached to said housing member and extending into said axial annular cavity for engagement with said annular ring member to create a frictional force therebetween to retain said second toothed ring in said disengaged position after said initial application of rotary force and prior to the further application of said rotary force to said piston member.
 6. The apparatus of claim 5 further comprising indication indicia on said housing member and said annular ring member to indicate the angular position of the object about said axis.
 7. The apparatus of claim 1 further comprising retaining means operably attached to said displacement assembly for engagement with said housing member to prevent further rotation of said article when said article is in a predetermined angular position upon the discontinuation of said application of rotary force to said piston member.
 8. The apparatus of claim 7 wherein said retaining means comprises:at least one spring-biased locking pin movably attached to said displacement assembly; and at least one engagement notch in said housing corresponding to each said predetermined angular position such that when said article is rotated to one of said predetermined angular positions, at least one said locking pin engages said corresponding engagement notch.
 9. An indexable workholding apparatus comprising:a longitudinal column member having a first longitudinal axis, said longitudinal column member operably supporting at least one pair of selectively movable jaw members for selectively clamping at least one workpiece therebetween, each said pair of selectively movable jaw members being selectively movable along a corresponding second longitudinal axis that is substantially parallel to said first longitudinal axis; first and second upstanding support members for rotatably and axially supporting said longitudinal column member therebetween for selective axial and rotational movement with respect to said first longitudinal axis; and an indexing assembly attached to said second support member and communicating with said longitudinal column member, said indexing assembly having a first toothed ring non-rotatably attached to said second support member and a second toothed ring axially and rotatably supported by said second support member and arranged in confronting relationship with said first toothed ring for selective meshing engagement therewith, said second toothed ring being attached to said longitudinal column member, said indexing assembly further comprising a piston member rotatably supported within said second support member and adapted to receive a rotary force, said piston member defining at least one first ramped surface, said indexing assembly comprising a displacement assembly attached to said second toothed ring and having a corresponding displacement member cooperating with each said first ramped surface of said piston member such that when a rotary force is initially applied to said piston member, each said first ramped surface causes said corresponding displacement member to axially bias said second toothed ring out of meshing engagement with said first toothed ring to a disengaged position and thereafter permitting said second toothed ring and longitudinal column member to be selectively rotated about said first longitudinal axis upon the further application of said rotary force to said piston member to rotate said longitudinal column member to a desired angular position about said first longitudinal axis, and biasing means supported by said second support member for selectively biasing said second toothed ring into said meshing engagement with said first toothed ring when said further application of said rotary force is discontinued.
 10. The apparatus of claim 9 wherein said piston member has a first bearing surface and wherein each said first ramped surface comprises a first ramped ball race in said first bearing surface and wherein said displacement assembly comprises a retaining ring attached to said second toothed ring and being coaxially aligned with said piston member and having a second bearing surface in confronting relationship with said first bearing surface of said piston member, said second bearing surface having a corresponding number of second ramped ball races therein that correspond to said first ramped ball races and cooperate therewith to define at least one ball cavity for receiving a corresponding ball member therein.
 11. The apparatus of claim 9 wherein said biasing means comprises at least one spring washer in said second support member for forcing said first and second toothed rings into engagement.
 12. The apparatus of claim 9 further comprising means for retaining said second toothed ring in said disengaged position after said initial application of rotary force and prior to the further application of said rotary force to said piston member.
 13. The apparatus of claim 12 wherein said means for retaining comprises:an axial annular cavity in said second support member; an annular ring member attached to the perimeter of said second toothed ring and arranged for axial travel within said axial annular cavity in response to said axial displacement of said second toothed ring; and at least one wiper member attached to said second support member and extending into said axial annular cavity for engagement with said annular ring member to create a frictional force therebetween to retain said second toothed ring in said disengaged position after said initial application of rotary force and prior to the further application of said rotary force to said piston member.
 14. The apparatus of claim 13 further comprising indication indicia on said housing member and said annular ring member to indicate the angular position of the longitudinal column member about said first longitudinal axis.
 15. The apparatus of claim 9 further comprising retaining means operably attached to said displacement assembly for engagement with said housing member to prevent further rotation of said longitudinal column member when said longitudinal column member is in a predetermined angular position upon the discontinuation of said application of rotary force to said piston member.
 16. The apparatus of claim 15 wherein said retaining means comprises:at least one spring-biased locking pin movably attached to said displacement assembly; and at least one engagement notch in said housing corresponding to each said predetermined angular position such that when said longitudinal column member is rotated to one of said predetermined angular positions, at least one said locking pin engages said corresponding engagement notch.
 17. The apparatus of claim 9 wherein said longitudinal column member has at least two longitudinal surfaces, each longitudinal surface having a longitudinal cavity therein extending along a corresponding second longitudinal axis and a corresponding center jaw removably attached thereto and corresponding first and second movable jaw-supporting members slidably supported within each said longitudinal cavity, said first and second movable jaw-supporting members having first and second extended portions, respectively, which each extend out of the corresponding longitudinal cavity for selective longitudinal movement therealong toward and away from the corresponding center jaw and a first jaw member corresponding to each said first extended portion and being removably attached thereto and a second jaw member corresponding to each said second extended portion and being removably attached thereto.
 18. Apparatus for selectively indexing an article about a first axis, comprising:a housing member; a first toothed ring non-rotatably attached to said housing member; a second toothed ring axially and rotatably supported by said housing member and arranged in confronting relationship with said first toothed ring for selective meshing engagement therewith, said second toothed ring being attached to said article; a piston member rotatably supported within said housing member and adapted to receive a rotary force, said piston member having at least one roller member operably attached thereto, said roller member arranged to rotate about a second axis that is substantially perpendicular to said first axis; a displacement assembly attached to said second toothed ring and having a ramped surface corresponding to each said roller member and cooperating therewith such that when a rotary force is initially applied to said piston member about said first axis, each said roller member causes said corresponding ramped surface on said displacement assembly to axially bias said second toothed ring out of meshing engagement with said first toothed ring to a disengaged position and thereafter permitting said second toothed ring and article to be selectively rotated about said first axis upon the further application of said rotary force to said piston member to a desired angular position about said first axis; and biasing means supported by said housing member for selectively biasing said second toothed ring into said meshing engagement with said first toothed ring when said further application of said rotary force is discontinued.
 19. The apparatus of claim 18 wherein said biasing means comprises at least one spring washer in said housing member for forcing said first and second toothed rings into engagement.
 20. The apparatus of claim 18 further comprising means for retaining said second toothed ring in said disengaged position after said initial application of rotary force and prior to the further application of said rotary force to said piston member.
 21. The apparatus of claim 20 wherein said means for retaining comprises:an axial annular cavity in said housing member; an annular ring member attached to the perimeter of said second toothed ring and arranged for axial travel within said axial annular cavity in response to said axial displacement of said second toothed ring; and at least one wiper member attached to said housing member and extending into said axial annular cavity for engagement with said annular ring member to create a frictional force therebetween to retain said second toothed ring in said disengaged position after said initial application of rotary force and prior to the further application of said rotary force to said piston member.
 22. The apparatus of claim 21 further comprising indication indicia on said housing member and said annular ring member to indicate the angular position of the object about said axis.
 23. The apparatus of claim 18 further comprising retaining means operably attached to said displacement assembly for engagement with said housing member to prevent further rotation of said article when said article is in a predetermined angular position upon the discontinuation of said application of rotary force to said piston member.
 24. The apparatus of claim 23 wherein said retaining means comprises:at least one spring-biased locking pin movably attached to said displacement assembly; and at least one engagement notch in said housing corresponding to each said predetermined angular position such that when said article is rotated to one of said predetermined angular positions, at least one said locking pin engages said corresponding engagement notch.
 25. An indexable workholding apparatus comprising:a longitudinal column member having a first longitudinal axis, said longitudinal column member operably supporting at least one pair of selectively movable jaw members for selectively clamping at least one workpiece therebetween, each said pair of selectively movable jaw members being selectively movable along a corresponding second longitudinal axis that is substantially parallel to said first longitudinal axis; first and second upstanding support members for rotatably and axially supporting said longitudinal column member therebetween for selective axial and rotational movement with respect to said first longitudinal axis; and an indexing assembly attached to said second support member and communicating with said longitudinal column member, said indexing assembly having a first toothed ring non-rotatably attached to said second support member and a second toothed ring axially and rotatably supported by said second support member and arranged in confronting relationship with said first toothed ring for selective meshing engagement therewith, said second toothed ring being attached to said longitudinal column member, said indexing assembly comprising a piston member rotatably supported within said second support member and adapted to receive a rotary force, said piston member having at least one roller member attached thereto and being rotatable about a second axis that is substantially perpendicular to said first longitudinal axis, said indexing assembly further comprising a displacement assembly attached to said second toothed ring and having a ramped surface corresponding to each said roller member and cooperating therewith such that when a rotary force is initially applied to said piston member, each said roller member rolls on said corresponding ramped surface to axially displace said second toothed ring out of meshing engagement with said first toothed ring to a disengaged position and thereafter permitting said second toothed ring and longitudinal column member to be selectively rotated about said first longitudinal axis to a desired angular orientation about said first longitudinal axis upon the further application of said rotary force to said piston member and biasing means supported by said second support member for selectively biasing said second toothed ring into said meshing engagement with said first toothed ring when said further application of said rotary force is discontinued.
 26. The apparatus of claim 25 wherein said biasing means comprises at least one spring washer in said second support member for forcing said first and second toothed rings into engagement.
 27. The apparatus of claim 25 further comprising means for retaining said second toothed ring in said disengaged position after said initial application of rotary force and prior to the further application of said rotary force to said piston member.
 28. The apparatus of claim 27 wherein said means for retaining comprises:an axial annular cavity in said second support member; an annular ring member attached to the perimeter of said second toothed ring and arranged for axial travel within said axial annular cavity in response to said axial displacement of said second toothed ring; and at least one wiper member attached to said second support member and extending into said axial annular cavity for engagement with said annular ring member to create a frictional force therebetween to retain said second toothed ring in said disengaged position after said initial application of rotary force and prior to the further application of said rotary force to said piston member.
 29. The apparatus of claim 28 further comprising indication indicia on said housing member and said annular ring member to indicate the angular position of the longitudinal column member about said first longitudinal axis.
 30. The apparatus of claim 25 further comprising retaining means operably attached to said displacement assembly for engagement with said second support member to prevent further rotation of said longitudinal column member when said longitudinal column member is in a predetermined angular position upon the discontinuation of said application of rotary force to said piston member.
 31. The apparatus of claim 30 wherein said retaining means comprises:at least one spring-biased locking pin movably attached to said displacement assembly; and at least one engagement notch in said second support member to each said predetermined angular position such that when said longitudinal column member is rotated to one of said predetermined angular positions, at least one said locking pin engages said corresponding engagement notch.
 32. The apparatus of claim 25 wherein said column member has at least two longitudinal surfaces, each longitudinal surface having a longitudinal cavity therein extending along a corresponding second longitudinal axis and a corresponding center jaw removably attached thereto and corresponding first and second movable jaw-supporting members slidably supported within each said longitudinal cavity, said first and second movable jaw-supporting members having first and second extended portions, respectively, which each extend out of the corresponding second longitudinal cavity for selective longitudinal movement therealong toward and away from the corresponding center jaw and a first jaw member corresponding to each said first extended portion and being removably attached thereto and a second jaw member corresponding to each said second extended portion and being removably attached thereto. 